Spinning of artificial filaments



Patented Dec. 29, 1936 UNITED STATES SPINNING or ARTIFICIAL FILAMENTS Camille Dreyfus, New York, N. Y., and William Whitehead, Cumberland, Md., assignors to Celanese Corporation of America, a. corporation of Delaware No Drawing. Original application November 10,

1928, Serial No. 318,583. Divided and this application October 6, 1933, Serial No. 692,429

11 Claims.

This invention relates to the manufacture of films or filaments, such as artificial yarns, fibres, bristles, straw, ribbons and the like, from solutions containing organic derivatives of cellulose.

This application is a division of our application S. No. 318,583 filed November 10, 1928.

An object of our invention is to prepare filaments or films containing organic derivatives of cellulose that are tougher and more pliable than those heretofore made.

Another object of our invention is to form films or filaments containing organic derivatives of cellulose from solution containing fatty acids or their glycerides as non-solvents or precipitants for the organic derivatives of cellulose.

Another object of our invention is to form films or filaments containing organic derivatives of cellulose that become delustered readily. Other objects of our invention will appear from the following detailed description.

Artificial filaments containing organic deriva' tives of cellulose have been prepared formerly by extrusion of solutions of the derivatives of cellulose in a volatile solvent through the orifices of a spinnerette into an evaporative atmosphere. Yarns made from such filaments are not as tough and pliable as may be desirable, and therefore the amount of twist that may be imparted to them, or the closeness with which such yarns may be knitted, is limited, since if a predetermined limit is exceeded, the same tend to' break or become materially weakened. Moreover such prior yarns or fabrics made from such yarns, become delustered in dyeing or scouring baths only at temperatures approaching that of boiling water, unless other delustering agents have been employed in the bath. We have found that if fatty acids or their glycerides that are non-solvents or precipitants for the organic derivatives of cellulose are added to the spinning solution containing the same, filaments may be formed that are tougher and more pliable, and also in some instances more readily delustered, than those made by the prior processes. Yarns made from such filaments among other desirable properties may have a much higher twist safely imparted thereto, they may be safely knitted closely on a circular knitting machine, and may in some instances be delustered in dyeing or scouring baths, at much lower temperatures than yarns made by the prior processes.

In accordance with our invention, We prepare filaments or films from solutions containing organic derivatives of cellulose in a suitable solity, may be filtered and then extruded through orifices of required size of a spinnerette either into a drying or evaporative atmosphere, as in dry spinning, or into a precipitating bath containing liquid such as water, kerosene, etc., as in wet spinning.

The filaments that may be formed by our invention may be the fine filaments having a denier of say 1 to 10 such as used for making yarns, or they may be much heavier having a denier of say 50 to 2000 denier to be used as artificial bristles for making brushes or for making artificial furs, etc. Our invention may also be advantageously employed for making tough and. pliable films for photographic purposes or other purposes, for making plastics, etc., where pliability is required.

Any suitable organic derivative of cellulose may be used in our invention. These may be organic esters of cellulose such as cellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate, or cellulose ethers such as ethyl cellulose, methyl cellulose and benzyl cellulose. This invention is particularly applicable in connection with acetone-soluble cellulose acetate having acetyl values of around 54% (determined as acetic acid).

Any suitable solvent may be employed for making the solution of the organic derivatives of cellulose. Example of such solvents are acetone, acetone and ethyl or methyl alcohol, chloroform, ethylene dichloride, ethylene dichloride and ethyl or methyl alcohol, methylene chloride and ethyl or methyl alcohol, etc.

Any suitable fatty acid or glyceride of a fatty acid that is a non-solvent or precipitant for organic derivatives of cellulose may be added to the solution of the same in accordance with our invention. Examples of fatty acids are stearic or oleic acids, while examples of glycerides of fatty acids are olein, stearin, caster oil, olive oil, etc. Mixtures of two or more of these fatty acids or their glycerides may be employed, and these may or may not be miscible with each other.

When solid fatty acids or their glycerides are used, it is advisable either to mix the same with the solution of the derivative of cellulose at a temperature high enough to melt such solid; or else first to dissolve the solid in a small quantity of a solvent for the same, such as benzene, and add. the solution so formed to the solution of the organic derivative of cellulose. The solution of the solid should preferably be added slowly to permit the same, which precipitates from its solution in the solvent employed for dissolving the organic derivative of cellulose, to become thoroughly disseminated or emulsified in colloidal form if necessary in the solution of the organic derivative of cellulose.

While we have found that the addition of even small quantities of fatty acids or their glycerides or to the spinning solution improves the properties of the filaments formed, we find that the maximum benefit is derived when amounts of such substances equal to 2.5 to 10% or more of the weight of the derivative of cellulose present are added to the spinning solution.

The lustre of the films, filaments or yarns produced by our method may be readily subdued in some instances depending upon the amount and nature of the non-solvent or precipitant added to the spinning solution. Thus, if a certain quantity of fatty acid or its glyceride based on the weight of the cellulose acetate present in the spinning solution is added, yarns formed from the same will deluster appreciably when subjected to water at C. If only one-half of this amount of fatty acid or its glyceride is added, the resultant yarn is delustered to a considerably less extent When treated with water under similar conditions. Thus, by controlling the amount of fatty acid or glyceride thereof added, the delustering properties of the yarn may be controlled.

Filaments, yarns or films formed by our invention are tough and pliable, which is surprising, since this would not be expected in theory. Thus, yarns made from our filaments may have a twist imparted thereto having 30 or 40% more turns per unit length than may the prior yarns, without reaching the weakening point. Yarns formed by our invention may be knitted 30% or more closer than yarns made by the prior process; that is, a circular knitted or warp knitted fabric may be formed having 30% more wales, courses or stitches than fabrics made from prior yarns. Yarns or bristles made by our process may be formed into stronger knots, while artificial straws or ribbons-or the like made by our process have improved plaiting qualities and may be subjected to considerably more severe processing.

When fatty acids or their glycerides are added to the spinning solution they might not always be entirely removed from the yarns or fabrics by the ordinary scouring method. Despite this fact, such yarns or fabrics may be subjected to such treatments as saponification, dyeing with vat dyes, basic dyes, or water insoluble dyes dispersed in colloidal solution, by normal methods with normal results.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention what we claim and desire to secure by Letters Patent is:

1. Artificial films or filaments containing organic derivatives of cellulose and a substance selected from the group consisting of fatty acids and their glycerides which are soluble in the solution from which said films or filaments are formed.

2. Artificial films or filaments containing cellulose acetate and a substance selected from the group consisting of fatty acids and their glycerides which are soluble in the solution from which said films or filaments are formed.

3. Artificial filaments containing acetone-soluble cellulose acetate and a substance selected from the group consisting of fatty acids and their glycerides which are soluble in the solution from which saidfilaments are formed.

4. A woven or knitted fabric containing yarns comprising the artificial filaments defined in claim 1.

5. A woven or knitted fabric containing yarns comprising the artificial filaments defined in claim 3.

6. A process of making acetate silk in the form of completed threads, fit for use as a finished product, which consists in providing an acetate spinning solution that contains a supplementary non-mineral oleaginous substance or a mixture of oleaginous substances of such nature that it will not evaporate at the temperatures used in the spinning process and in a proportion to the cellulose acetate as to be in solution in the spinning solution, spinning by the dry or evaporative method threads from that solution, the threads emerging from the solution with such substance incorporated therein and retaining in the threads in their spun condition said substance incorporated therein.

7. Process for the manufacture of artificial filaments, foils and like materials, which comprises shaping a solution of an organic derivative of cellulose in a medium comprising a solvent for the organic derivative of cellulose and containing, dissolved therein, a precipitant for the organic derivative of cellulose selected from the group consisting of fatty acids and their glycerides and coagulating the shaped products without removing said precipitant therefrom.

8. Process for the manufacture of artificial filaments, which comprises extruding through fine orifices a solution of an organic derivative of cellulose in a medium comprising a solvent for the organic derivative of cellulose and containing, dissolved therein, a precipitant for the organic derivative of cellulose selected from the group consisting of fatty acids and their glycerides and coagulating the extruded filaments without removing said precipitant therefrom.

9. Process for the manufacture of artificial filaments, which comprises extruding through fine orifices into an evaporative atmosphere a solution of an organic derivative of cellulose in a medium containing a volatile solvent for the organic derivative of cellulose and containing, dissolved therein, a precipitant for the organic derivative of cellulose selected from the group consisting of fatty acids and their glycerides, said precipitant being substantially unvolatilized during the extrusion of the filaments.

10. Process for the manufacture of artificial filaments, which comprises extruding through fine orifices into an evaporative atmosphere a solution of cellulose acetate in a medium containing a volatile solvent for the cellulose acetate and containing, dissolved therein, a precipitant precipitant for said cellulose acetate selected from the group consisting of fatty acids and their glycerides, said precipitant being substantially unvolatilized during the extrusion of the filaments.

CAM'ILIE DREYFUS. WILLIAM WHITEHEAD. 

